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Old 2017-04-20, 16:24   #8
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Jul 2009

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Originally Posted by VBCurtis View Post
Are you saying n! +1 up to n!+n are all composite? I must not understand what you mean by "anything between 1 and n", because there are lots of examples where n!+1 are prime.
I think they messed up on saying 1 but we can prove that n!+2 to n!+(nextprime(n+1)-1) are all composite. edit:of course this isn't necessarily the first time this gap happens the primorial also works on the same logic: 2*3*5+2 until 2*3*5+(7-1) are all composite.

Last fiddled with by science_man_88 on 2017-04-20 at 16:29
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